Fantasy can Never beat Reality as it lacks Truth?

Kant first questions the intelligibility of the very concept of an absolutely necessary being, considering "whether I am still thinking anything in the concept of the unconditionally necessary, or perhaps rather nothing at all". He examines one way of understanding the concept, which looks to examples of necessary propositions, e.g. "a triangle has three angles". But he rejects this account for two related reasons. First, no absolutely necessary judgments will ever yield an absolute necessity for things and their existence: e.g., "a triangle has three angles" yields only the conditioned necessity that, if a triangle exists, then necessarily three angles exist. Thus even if we defined a concept of a thing X so that "X exists" were a necessary judgment, all that would follow is the conditioned necessity that, if X exists, then necessarily X exists. Second, since contradictions arise only when we keep the subject and cancel the predicate (e.g., keeping God and canceling omnipotence), and since judgments of nonexistence cancel both the subject and the predicate, therefore no judgment of nonexistence can involve a contradiction. Kant concludes that there is a strong general case against the intelligibility of the concept of an absolutely necessary being.

Second, Kant argues that if we include existence in the definition of something, then asserting that it exists is a tautology. If we say that existence is part of the definition of God, in other words an analytic judgment, then we are simply repeating ourselves in asserting that God exists. We are not making a synthetic judgment that would add new information about the real existence of God to the purely conceptual definition of God.

Third, Kant argues that "'being' is obviously not a real predicate" and cannot be part of the concept of something. That is, to say that something is or exists is not to say something about a concept, but rather indicates that there is an object that corresponds to the concept, and "the object, as it actually exists, is not analytically contained in my concept, but is added to my concept". For objects of the senses, to say that something exists means not that it has an additional property that is part of its concept but rather that it is to be found outside of thought and that we have an empirical perception of it in space and time. A really existing thing does not have any properties that could be predicated of it that differentiate it from the concept of that thing. What differentiates it is that we actually experience it: for example, it has shape, a specifiable location, and duration. To give an example of Kant's point: the reason we say that horses exist and unicorns do not is not that the concept of horse has the property of existence and the concept of unicorn does not, or that the concept of horse has more of that property than the concept of unicorn. There is no difference between the two concepts in this regard. And there is no difference between the concept of a horse and the concept of a really existing horse: the concepts are identical. The reason we say that horses exist is simply that we have spatio-temporal experience of them: there are objects corresponding to the concept. So any demonstration of the existence of anything, including God, that relies on predicating a property (in this case existence) of that thing is fallacious.

Thus, in accordance with the second and third arguments, the statement "God is omnipotent" is an analytic judgment that articulates what is already contained in and implied by the concept of God, i.e. a particular property of God. The statement "God exists" is a synthetic judgment of existence that does not assert something contained in or implied by the concept of God and would require knowledge of God as an object of that concept. What the ontological argument does is attempt to import into the concept of God, as though it were a property, the synthetic assertion of the existence of God, thereby illegitimately and tautologically defining God as existing. In other words, it begs the question by assuming what it purports to prove.

But, fourth, Kant argues that the concept of God is in any case not the concept of one particular object of sense among others but rather an "object of pure thought", of something that by definition exists outside the field of experience and of nature. With regard to unicorns, we can specify how we could determine that unicorns exist, i.e. what spatio-temporal experience of them would look like. With regard to the concept of God, there is no way for us to know it as existing in the only legitimate and meaningful way we know other objects as existing. And we cannot even determine "the possibility of any existence beyond that which is known in and through experience".